The Departments of Biochemistry-Molecular Biology of the University of California, Berkeley, has established a Mutagenesis Center under sponsorship of the National Institute of Environmental Health Sciences. This center unifies the efforts of a number of research groups in the Department working on various aspects of mutagenesis. A growing awareness that damage to the integrity of nucleic acids by environmental mutagens is a major problem in public health has directed many members of the Department towards more practical applications of their basic research. Eleven faculty members participate in the Center. The Mutagenesis Center's main focus in on the following research areas: 1. The detection and characterization of environmental mutagens and carcinogenes. 2. The study of mechanisms of mutagenesis and relation to carcinogenesis. 3. The study of the role of DNA damage in human disease, aging and evolution. 4. The study of DNA repair and other enzymic defenses against DNA damage and mutagenesis. 5. The study of basic mechanisms and dynamics of the genetic apparatus and chromosomes in higher organisms as related to genetic stability and toxic agent action.